Coil dispensers are used as a source or supply of coil material for many operations. In one application, strapping material is supplied on a coil for use in a strapping machine. Various types of strapping machines are well known in the art and will be recognized by those skilled in the art.
The strapping material is fed from the coil to the strapping machine. The coil is supported on a coil dispenser. The dispenser provides a controlled source of the strapping material to the strapping machine. Functionally, the dispenser must permit feeding the strapping material to the strapping machine (when there is a demand) with little resistance on the material. The dispenser must also, however, prevent the coil from free-rolling (free rotation) whereby strapping material continuously feeds from the coil when there is no demand for strapping material To this end, the dispenser must include provisions to slow or brake the coil from free rotation upon a drop in demand.
One known dispenser includes a shaft about which the coil is mounted for rotation. A circular side plate is mounted to a side of the coil for rotation therewith. The shaft is positioned on a frame. To install a strapping material coil, the dispenser is opened, the side plate is removed and laid on a side. The coil is positioned on the plate, and the plate and coil are reinstalled on the dispenser.
The dispenser includes a dancer arm that pivots about the coil shaft. A roller is positioned at an end of a dancer arm opposing the arm axis of rotation. A brake assembly is mounted to the dancer arm for movement into and out of engagement with the side plate. The dancer arm is biased such that the brake is in engagement with the side plate.
The dispenser includes a second roller spaced from the dancer arm roller, mounted to the frame. Strapping material is fed from the coil, around the dancer arm roller and the frame roller. The strapping material is then fed to the strapping machine. As demand increased, the dancer arm pivots, disengaging the brake. Demand on the strap accelerates the coil, thus dispensing strap therefrom As demand drops, the dancer arm returns to its braking state, and the coil is slowed to prevent free-rolling and non-demand feed.
Another type of single coil dispenser includes a fixed arm and a dancer arm. The dancer arm pivots about an axis of rotation spaced from the coil axis. Each the dancer arm and the fixed arm include a plurality of rollers positioned one adjacent the other (i.e., side-by-side), at an end of the respective arms. The dancer arm is biased away from the fixed arm so as to increase the distance therebetween. This provides an accumulation region in which a length of strapping material accumulates in a controlled and ordered arrangement as it is drawn from the coil. This dispenser includes a complex arrangement of chains and sprockets to provide a braking force to prevent free-rolling of the coil.
Although both of these dispensers work well for their intended functions, they both have their drawbacks. In the single arm dispenser arrangement, the speed at which strapping material can be supplied (or drawn from the coil) is limited. That is, although this type of dispenser works well with slower speed strapping machines (those operating at about 5 feet of strap consumed per second) it does not function well with faster machines. Specifically, in this dispenser arrangement, there is no region for significant xe2x80x9caccumulationxe2x80x9d of strap that can be fed to the strapping machine from the dispenser at rest. As such, when used with faster strapping machines, this dispenser has been found to cause binding of the strapping machine feed wheels due to its slow delivery of strapping material.
While these drawbacks may be addressed by the two arm dispensers, this dispenser is quite costly to manufacturer and is complex in design. Specifically, the braking arrangement, which uses chains and sprockets, greatly increase the cost of the dispenser while at the same time increasing the complexity of the overall device. In addition, because the fixed and movable dancer arms each include a plurality of side-by-side rollers, when new strapping material is fed to the strapping machine, it must be laced or threaded around these rollers. In that these rollers are arranged side-by-side with one another, this lacing or threading can be quite time consuming and confusion can result.
In addition, it has been found that both of these arrangements require considerable time and manpower when replacing a coil of strapping material. In addition, when replacing a coil of strapping material, the strapping machine must be taken out of service until a new coil is placed on the dispenser and the dispenser placed back in service. This increases the xe2x80x9cdowntimexe2x80x9d of the machine and can adversely impact the overall manufacturing or packaging operation.
Accordingly, there exists a need for a coil dispenser for dispensing strapping material from a coil. Preferably, such a dispenser includes provisions for mounting multiple coils thereto to reduce downtime when replacing strapping material coils. More desirably, such a dispenser provides sufficient accumulation of strapping material so that high-speed strapping operations are fully supported. Most desirably, such a dispenser permits straight forward use with minimal lacing required when starting new coils. Further, such as dispenser uses a stem that is readily accessible for operator attention.
A multiple coil dispenser supports at least two associated coils for dispensing a flexible material from one of the coils. The dispenser includes a frame and at least one coil support for supporting the associated coils for rotation.
A fixed arm is mounted to the frame and includes a plurality of rollers positioned longitudinally therealong. Preferably, the arm is mounted to the frame at an upward angle.
A movable or dancer arm is mounted for movement toward and away from the fixed arm. Preferably, the movable arm is biased, by a spring, away from the fixed arm. In a present embodiment, the movable arm pivots toward and away from the fixed arm. The movable arm, like the fixed arm, has a plurality of rollers positioned longitudinally therealong. The fixed arm rollers and the movable arm rollers are disposed on their respective arms to nest with one another when the movable arm is disposed adjacent the fixed arm.
In a current embodiment, retainers are associated with at least some of the rollers. The retainers can be configured as one or more retainer brushes, each disposed to contact strapping material between it and its respective roller. Alternately, the retainers can be configured as secondary rollers disposed to maintain contact of the strap with the (primary) rollers.
The dispenser includes a brake assembly operably connected to the movable arm between an engaged position when the movable arm is moved away from the fixed arm and a disengaged position when the movable arm is moved toward the fixed arm. The brake assembly can be configured as a sheave mounted for rotation with the associated coils and a braking belt fixedly mounted to the dispenser at a first end and mounted to the movable arm at a second end. The braking element is configured to apply a braking force to the sheave to stop rotation of the coil as the movable arm moves (pivots) away from the fixed arm.
The arms define a space or accumulation region therebetween. The accumulation region varies in size as the movable arm moves toward and away from the fixed arm. That is, the accumulation region increases in size as the movable arm moves away from the fixed arm and decreases in size as the movable arm moves toward the fixed arm. In this manner, a significant amount of strap is accumulated in the accumulation region when the movable arm is farthest from the fixed arm.
In order to facilitate feeding strap from either of the coils to the centrally positioned arms, the dispenser includes a bifurcated strap chute. The chute includes two first or feed sections and an outlet section. Between inlets and a juncture with the common outlet, at the feed sections, the chute sections can include first and second, reversing helical sections. The helical sections facilitate redirecting the strap from the location at which the strap leaves the coil, to a central location for traversing through the fixed and movable arms.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.